Nonlinear circuit device

ABSTRACT

A nonlinear circuit consisting of first and second circuits. The first circuit comprises a power source, an inductance element L1 and a capacitance element C connected in an oscillating arrangement. The second closed circuit comprises said capacitance element, an inductance element L2 and a voltage responsive switching element. The second closed circuit is controlled for operation under either oscillating or nonoscillating condition depending on the necessary output voltage.

United States Patent Sumi et al. [4 1 Jan. 18, 1972 [54] NONLINEAR CIRCUIT DEVICE References Cited [72] Inventors: Seiji Sumi; Isao Kaneda, both of Otsu, UNITED STATES PATENTS Japan 1,758,359 5/1930 Famsworth ..331/50 [73] Assignee: New Nippon Electric Company Ltd.,

Osaka, Japan Primary Examiner-Herman J. Hohauser [22] Filed: Feb- 26, 1970 gitgzilfgr-l-Emanuel R. Posnack, Alan K. Roberts and Julian [21] Appl. No.: 14,324

ABSTRACT [30] Foreign Application Priority Data A nonlinear circuit consisting of first and second circuits. The first circuit comprises a power source, an inductance element Sept. 10, 1969 Japan ..44/7l845 L1 and a capacitance element C connected in an oscillating rangement. The second closed circuit comprises said [52] US. Cl. ..307/l06, 331/50 capacitance element, an inductance element L2 and a voltage [51] Int. Cl. ..H03k 3/00 responsive Switching element The second closed circuit is [58] Field of Search ..33 1/46, 50; 307/106, 107, 108,

controlled for operation under either oscillating or nonoscillating condition depending on the necessary output voltage.

19 Claims, 10 Drawing Figures NONLINEAR CIRCUIT DEVICE BACKGROUND I Field of the Invention This invention relates to nonlinear circuits and more particularly to structurally simple high-voltage generators capable of delivering very large amplitude voltages and instantaneous power.

2. Description of the Prior Art It is generally known that a very large amplitude voltage and instantaneous power are required to turn on a discharge lamp or to ignite an internal-combustion engine or the like. For this purpose, stepup transformers have been used. In cathode-ray tubes, a blocking oscillator circuit is used, providing a special waveform such as a saw-tooth wave. A variety of this type of power converter circuit is now available for use according to requirements.

SUMMARY OF THE INVENTION An object of this invention is to provide an improved nonlinear circuit consisting of a first closed circuit comprising at least one power source and further comprising an inductor and a capacitor, which are arranged for a certain oscillating condition; and a second closed circuit comprising said capacitor, an inductor and a voltage-responsive switch.

It has been discovered, as one aspect of the invention, that the above-mentioned nonlinear circuit can be used as an oscillator circuit or a pulse generator circuit depending on whether the second closed circuit is in oscillation or nonoscillation condition. The oscillating condition results when where the first closed circuit has a capacitance C, inductance L, and resistance R, including the inherent resistance component thereof. With this arrangement, it is found that a markedly amplified output voltage can be obtained.

It will not be assumed that the second closed circuit has a capacitance C, inductance L and resistance R including the inherent resistance component thereof, wherein the capacitor is same as in the first closed circuit, and

preferably near resonance condition as expressed by 2'nf L I IZ'nf C (where f is frequency of the second closed circuit), and that the inductance L, is larger than L and the second closed circuit is set for oscillating condition. By this arrangement, an oscillator circuit is formed. This circuit is capable of amplifying a given input voltage to a markedly large output oscillating voltage, which is delivered across the capacitance C at the output terminals. This output voltage can be effectively used for any circuit which requires a high voltage to turn on a discharge lamp or to ignite an intemal-combustion engine or the like, or for the saw-tooth wave generator for a CRT. In other words, the invention makes it possible to fonn starting circuits or oscillator circuits effectively with very simple arrangements.

When the second closed circuit is set for nonoscillating condition where R 1 IL? 0L.

and L, L (the references denote the same circuit elements as previously), then a pulse generator circuit is formed whereby a pulse voltage whose peak value is very high can be obtained across the output terminals. This pulse voltage can be effectively utilized for the turning on of a discharge lamp or the like. This simplified nonoscillating circuit is effectively applicable to all kinds of devices which need pulse voltage.

In connection with the above-mentioned circuit. generally, the value of the first inductance element L, of the first closed circuit is determined to be larger than that of the second-inductance element L Therefore the influence of the oscillating condition due to variation of values in the second inductance element L is substantially negligible on the first closed circuit.

Brief Description of the Drawings FIG. 1 is acircuit diagram showing the principles of the invention;

FIGS. 2(a)-(c) are equivalent circuit diagrams of FIG. 1 showing the operation of the invention;

FIG. 3 is a waveform diagram showing an output voltage appearing across the capacitor in FIG. 1;

FIG. 4 is a circuit diagram showing a nonlinear circuit device embodying this invention;

FIG. 5 is a circuit diagram showing an arrangement wherein the first and second closed circuits of FIG. 4 are electromagnetically coupled with each other to permit controlling the oscillator energy;

FIG. 6 is a circuit'diagram showing an arrangement wherein the output voltage can be derived in a trapezoidal waveform;

FIG. 7 is a circuit diagram showing a multistage arrangement; and

FIG. 8 is a diagram showing a circuit for stepping up the output voltage, this circuit being suited for pulse generation according to the invention.

DETAILED DESCRIPTION FIG. 1 shows a circuit consisting of a first closed circuit which comprises a DC source I, a power switch 2, a first inductor 3 and a capacitor 4; and a second closed circuit which comprises said capacitor 4, a second inductor 5 and a voltage responsive switch 6 which is rendered conductive by a specific voltage.

The first closed circuit is set for an oscillating condition by determining the values of the circuit elements L, and C. The constants of the circuit elements of the second closed circuit are detennined to set this circuit for an oscillating or nonoscillating condition depending on the uses which will be described later.

The operation of the second closed circuit under the oscillating condition will be specifically described below by referring to the circuit diagram and other circuit diagrams showing embodiments of the invention.

The operation of the logical circuit of FIG. I under the oscillating condition will next be explained in operating sequence:

I. First Charging Process In FIG. 1, when the power switch 2 of power source I for DC voltage E is closed, this state 1 is expressed equivalently by the circuit in FIG. 2(a) since the voltage responsive switch 6 is in the nonconducting state at this moment. In this equivalent circuit, when the power switch 2 is assumed to be closed at time i=0, the current i, and the voltage across the capacitor 4, namely the output voltage e varying as lapse of time are expressed by the following equations:

. E 1 1, sin

In other words, the output volta e e, becomes twice the power source voltage E at time t=7r L,C. Practically, the operating breakover voltage If, of the voltage responsive switch 6 becomes smaller than the output voltage e,.. Because there is a phase difference of 1r/2 between the voltage and current. the nonconducting state is maintained until the time t after the power switch 2 has been closed. This operation is shown by the range between 0 and I of the characteristics curved in FIG.

3, for example, in case that the breakover voltage V of the voltage responsive switch is equal to 2E. II. First Discharging Process When the value of the output voltage e, approaches its maximum point I, it becomes possible for the inductor 5 of the second closed circuit to pass a lagging current. The capacitor 4 starts discharging its charge into the second closed circuit. Since the current i, flowing in the first closed circuit at the instant of discharge is zero, the second closed circuit operates independently. Under this condition, the logical circuit of FIG. 1 is expressed by the equivalent circuit in FIG. 2(b). In this equivalent circuit, when the time at which the voltage responsive switch 6 turns on is assumed I =0, the current i and the voltage e across the capacitor 4 varying as lapse of time are expressed by the following equations:

. 2E 1 1 sin ti \/g; 2 w/L C wherein e is the maximum value of output voltage e The polarity of e is reversed at time t ='rr L C after the switch 6 has turned on. The current keeps flowing in the circuit until time t =7IYITC after the switch 6 has been closed. When the output voltage becomes negatively twice the power source voltage E (namely e =2E), the current i becomes zero, and it becomes impossible for the voltage responsive switch 6 to maintain its holding current. This makes the switch 6 nonconducting. This operation is shown by the range between I and II of the output voltage characteristic curve in FIG. 3.

III. Second Charging Process When the voltage responsive switch 6 becomes nonconducting under the condition where the polarity of the voltage e,. across the capacitor 4 is reversed, the circuit of FIG. 1 is expressed by the equivalent circuit in FIG. 2(0). The voltage (e =2E) across the capacitor 4 is added to the power source voltage E, and the equivalent power source voltage will be increased to SE. In the same way, the power source voltage is added to itself in succession. Therefore, when the number of a charge (i.e., whether it is the first or second charge or same subsequent charge) is assumed n, the voltage across the capacitor e, is expressed by e s E (n+ I) (5) This operation is shown by the range between II and III of the e characteristic curves in FIG. 3.

A series of the above operations is repeated and, theoretically, the amplitude of the oscillation grows infinitely. The oscillating period is determined by L,C when the voltage is in the increasing turn, or by L G when the voltage is in the reversing turn.

IV. Function of Inductance L It is believed that the amplitude voltage phenomenon is achieved by using a particular inductance element L Though the breakover voltage V of the voltage responsive switch 6 is selected as equal to or smaller than the maximum value of the output voltage e, (the 2E of equation (2) for the first charging process), and as also the inductance voltage 2, appearing between the terminals of the inductance element L is substantially zero in the first charging process, the polarity reversion of e, is caused by the second charging process and before the reachable maximum value 2E expressed in the equation (2) is achieved. When the coil for L is made with a core of ferrite material to form proper stray capacitance, the terminal voltage e, of the inductance element L does not respond as L di )/dt during the switching-off state.

Thus, at a time after the current i equals zero, the voltage e, having a back swing characteristic remains. If the variation of this characteristic is nearly equal to the variation of the equation (2), the difference voltage V, between e and e, which is applied to the voltage responsive switch 6, requires a considerably long time to reach V Regardless of this fact, e, is developed by the characteristic of e,. When V, is equal to V the second closed circuit having high operational quality is operated. The current i, at a given moment will be developed by repeating discharge. Thereby the developed current i reduces the value of the nonlinear inductance L and causes securing the voltage e,. for stable oscillation.

Practically, however, the output voltage e is limited to a certain definite value since the inductor, connecting lines and so forth have resistance components.

An embodiment of the invention in which the second closed circuit is in the oscillating condition will next be explained below with reference to FIG. 4.

FIG. 4 shows a circuit embodying this invention. This circuit consists of a first closed circuit comprising a DC source 1, a first inductor 3, a capacitor 4 and a resistor 7; and a second closed circuit comprising said capacitor 4, a second inductor 5, a voltage responsive switch 6 and a resistor 8. In this circuit, an AC power source may be used instead of said DC source for the first closed circuit.

It is preferable that ferrite magnetic material which has a small inductance loss and ferrimagnetism be used for the in ductor 5, and that a static solid-state switch such as a thyristor be used for the voltage responsive switch of the second closed circuit.

The constants of the circuit elements are indicated by C for the capacitor 4, L, and L for the first and second inductances 3 and 5 respectively, R for resistance component in the first closed circuit including the resistance element 7 and R for resistance component in the second closed circuit including the resistance element 8.

When the internal resistance of the inductor 3 is not sufficient for the resistance R a further resistance element is additionally used. Such external resistance element is the resistance element 7. Similarly, an external resistance element 8 may be added to the internal resistance of the inductor 5 to obtain reasonable resistance value R for the second closed circuit. However, this external resistance element 8 is not always necessary for the second closed circuit. This is because, to obtain a high-voltage generator device, the operational quality Q of the second closed circuit must be better than that Q, of the first closed circuit.

The oscillating and turn-on conditions in the circuit of FIG. 4 and the oscillating period and output voltage available from the second closed circuit will next be described below:

I. Oscillating Condition When the first and second closed circuits are both set for the oscillating condition, the following inequalities are established:

The following relationship is determined in order not to delay the reversing process following the amplifying process:

L| L2 The best condition for oscillation is in the resonance of the second closed circuit, that is 21rf L =l/2'n'f C. wherein f is a frequency of the second closed circuit. II. Tum-on Condition It is statically sufficient to effect turn on that the relationship between the power source voltage E and the operating voltage V of the voltage responsive switch be determined as follows:

E a V00 However, even if V is larger than E due to transient phenomenon, turnon can be realized kinetically by the use of power switching. For example, when L, L the following condition must be satisfied:

1 where where K, and K constant In any case, it is evident that this oscillating period is greatly different from that in the conventional saw-tooth wave oscillator (relaxation oscillator) of LC oscillator. In case the oscillating frequency is smaller than 100 kI-Iz., Tis nearly equal to T,. V. Output Voltage The output voltage is also so complicated that it cannot be expressed by a simple equation. Experimentally, the output voltage e, was found to be about 50 times the power source voltage.

The maximum value of the output voltage is expressed substantially as;

2 oma: K4

where K, and K, constant Why so high an output voltage can be obtained is due to the fact that the discharge sustaining period T of the second closed circuit can be made much shorter than the charge sustaining period T, of the first closed circuit under the condition wherein operational quality 0 of the second closed circuit is very high and the second closed circuit is set at nearly resonance condition. As a result, the relationship i, i is instantaneously established. Such voltage is far greater than the operating voltage V,,,, of the switching element 6 of the thyristor. In this operation, the switching element 6 will not reach breakover" since there is a phase angle difference between the output voltage (condenser voltage) and the oscillating current in the second closed circuit. In other words, the voltage is increased during the time corresponding to this phase difference. Seen from the output terminal of the second closed circuit, for example, the voltage applied to the switching element 6 is blocked by the inductor 5 for a certain period of time.

It is believed that there is a certain characteristic of the particular inductance element 5, which is of a nonlinear type, which produces a developed oscillating voltage. More particularly, when the magnetic flux of the core of inductor 5 is in saturated state during the conducting state of the voltage responsive switching element 6, due to the current i having a relatively high peak and flowing into the second closed circuit (due to the high operational quality 0 of the second closed circuit) when the switching element 6 is opened, the inductor 5 permits inducing a relatively big backswing voltage in connection with the distributed stray-capacitance factor thereof. This backswing voltage blocks the developed condenser output voltage v which will be applied to the switching element 6 through the inductor 6. Thus, the terminal voltage e, of the inductor 5 and the terminal voltage e, of the capacitor 4 cancel each other so that the output voltage e may develop to so high a value. Also, energy of the capacitor 4 may be stored proportionally to the square of the maximum value of output voltage v The output voltage takes a waveform such as a saw-tooth round saw-tooth wave, triangular wave, round triangular wave, or the like depending on the velocity of variation in the energy stored in or released from the inductor. The frequency of the output voltage is determined by the tumoff time inherent in the thyristor which in a component such as a silicon symmetrical switching element is experimentally detennined to be between 5 kHz. and I0 MHz.

According to the results of experiments with the circuit shown in FIG. 4, an output voltage e, of 360 v. was obtained from a source voltage of 60 v., wherein each of the elements had values as follows:

R, =69.5Q,- R Negligible as a few ohms, C=0.03p.F, Q2=(/R,) (La/C) =100, L, =565 mh. L, =79 mh. (measured by the bridge method at 1 kHz. and

A Mn-Zn ferrite core was used for L, and L and the voltage responsive switch was a symmetrical switching element consisting of an NPNPN five-layer diode.

Instead of a DC source, an AC power source may be used. When an AC of commercial frequency is used, this frequency is very low compared with the oscillating frequency. Therefore the oscillator will have a varying frequency due to variation in the instantaneous value of the power source voltage according to the approximate expression of the following equawhere l,and Z, are the current and impedance of the first closed circuit. Assume that the value of L is suitably determined as, for example, such that the magnetic body is saturated by the current i and its characteristic is varied along a reducing curve, the envelope of the oscillating voltage can be controlled.

In the succeeding embodiments, an AC power source 1' is used. Instead of AC power source, the DC source in FIG. 4 may be employed. The same components as in FIG. 4 are indicated by common references. The resistors 7 and 8 are omitted.

FIG. 5 shows another embodiment of the invention, wherein an inductor 9 having a primary coil 10 and a secondary coil 11 which are electromagnetically coupled with each other is disposed in the second closed circuit. The two coils of the inductor 9 are connected with each other either magnetizingly or demagnetizingly, and their inductances are determined so as to be adequately varied by i By this arrangement, the inductor 9 is fully saturated (L =0) at an arbitrary phase angle of half-cycle of the power source voltage so that the inductance is zero and thus the oscillation can be stopped and the oscillating energy can be controlled. In this embodiment, the first inductor 3 may be omitted, because inductance L, is provided by the coil 10.

FIG. 6 shows another embodiment of the invention, wherein a very small inductor 12 is connected in series with the capacitor 4. In this circuit, the energy stored in the inductor l2 during flow of the discharge current is released in the charging process. As a result, the output voltage across the capacitor 4 takes a trapezoidal waveform. In this manner, the oscillating waveform can be controlled.

FIG. 7 shows still another embodiment of the invention, wherein a capacitor 4, an inductor 5' and a voltage responsive switch 6' are intermediately connected thereto whereby a multistage oscillator is realized. In this circuit, the inductor 5' is operated as the inductance of the second closed circuit in the first stage and also as the inductance of the first closed circuit on the second stage. The output voltage of the first stage is increased by operating the inductor as a step-up transfonner. The stepped up voltage van be applied to the second stage circuit. Similarly, the number of stages may be increased to more than three to obtain an oscillating output of special waveform.

FIG. 8 shows another embodiment of the invention. In this circuit, the oscillating voltage is increased by the turn ratio between the primary and secondary windings of the transformer l2 and the capacitor charging and discharging current is used to excite the core of the transformer 12 in the same direction and thus the envelope of the output voltage approaches a rectangular waveform.

When the second closed circuit is set for the nonoscillating condition, the discharge current varies in the form of a exponential function, and the output voltage takes an impulse waveform. When this operation is considered in connection with the circuit in FIG. 4, the first charging process is the same as in the oscillating condition, but the first discharging process goes in the following manner: Namely, the relationship between the two inductances is L, L and the second closed circuit operates independently. The current i is in impulse fonn and can be expressed by the following equation:

E 2 BL;

where In this circuit, such oscillating current as flows under the oscillating condition does not flow and the voltage responsive switch 6 maintains its conducting state. Thus, the current from the power source flows through the inductors 3 and 5. In this case, if the power source is AC said impulse voltage is produced when the polarity of the flowing current is reversed. When the current is decreased to zero, the saturated magnetic flux density B, is varied but is maintained due to the square hysteresis characteristic of the core which has a curve maintaining a substantially saturated magnetic flux condition until the reversing of current polarity. However, when the current i is reversed, the capacitor 4 charges and then discharges. The discharge current i of the capacitor 4 produces the magnetic flux within the core of the inductor 5 in reversed direction relative to the above-mentioned flux density 3,, so the magnetic flux density +B, is abruptly changed to the reverse magnetic flux density B,. This abrupt variation of the magnetic flux causes a large inductance L in the inductor 5, and thereby a high pulse voltage occurs in the second closed circuit. This impulse voltage is unidirectional and there is no possibility of effecting a voltage inversion amplifying process as in the foregoing oscillating condition. I. Impulse Voltage Generating Condition In order to substantially isolate the first closed circuit from the impulse current, the relationship between the two inductances must be Also, the following relationship must be established since the first closed circuit is set for the oscillating condition, and the second closed circuit for the nonoscillating condition:

In this circuit, tum-on operation is performed under the same conditions as in the foregoing oscillating condition.

According to the embodiment, for example, of FIG. 8, this nonlinear circuit is suited for pulse generation by setting the second closed circuit for the nonoscillating condition. Practically, the value of inductance L, is determined to be smaller than that in the oscillating condition. In this circuit, one end of the capacitor 4 is connected to an intermediate tap a of the inductor l2 and thus the impulse voltage is stepped up. In one experimental circuit device, a magnetic material having a square-loop hysteresis curve is used for the core of the induction 12 in order to increase the flux variation level from the saturation flux level to the reversely characteristic flux saturation level. The value of the inductance ranges in the order of from microhenries to megahenries, and thus an impulse wave output voltage e of more than l0,000 v. is obtained with a 200 v. power source voltage.

According to this embodiment, the width of the impulse voltage is about 0.1 to several tens of microsecond. When the circuit of this invention is set for pulse generation, inductor 12 as inductance L is composed of the square-loop hysteresis magnetic materials such as 50 percent nickel-iron alloy produced as Sendelta" by Tohoku Metal Industries, Ltd. in Japan.

As has been described above, the invention makes it possible to obtain a large amplitude output voltage through very simple arrangement. The circuit device of this invention can therefore be widely applied to discharge lamp turnon devices and similar systems. The impulse wave voltage generator circuit of this invention is particularly useful when applied to turnon devices for intemal-combustion engines, and the output voltage of the saw-tooth wave oscillator circuit can be effectively used for the sweep circuits of static deflection cathoderay tubes. Also, according to the invention, the trapezoidal wave oscillating output voltage has a large oscillating energy and therefore this output can be effectively used for the purpose of biasing the magnetic body. Because a voltage responsive switching element having a sufficiently large breakover current capacity is employed in combination with a serially connected inductor, the circuit reliability is greatly increased.

The invention, because of its high practicality as evident from the foregoing description, can be put to use in many ways and in numerous fields, particularly when combined with a suitable waveform modifier.

We claim:

1. A nonlinear circuit device consisting of a first closed circuit which comprises a power source, a capacitance element and a first inductance element in interconnected relation; and a second closed circuit which comprises a voltage responsive switching element, a second inductance element and said capacitance element of the first closed circuit in interconnected relation, the second closed circuit being coupled with said first closed circuit by said capacitance element; said first inductance element and capacitance element having values putting the first closed circuit in oscillating condition; said circuit device being in the form of an oscillator circuit and said elements having values to satisfy the following conditions:

L,: inductance value of the first inductance element L inductance value of the second inductance element C: capacitance value of the capacitance element R,: resistance value of the first closed circuit R resistance value of the second closed circuit to: 21rf and f, is a frequency of the second closed circuit.

2. A nonlinear circuit device as claimed in claim 1, wherein the second inductance element includes a core of ferrite magnetic material.

3. A nonlinear circuit device consisting of a first closed circuit which comprises a power source, a capacitance element and a first inductance element in interconnected relation; and a second closed circuit which comprises a voltage responsive switching element, a second inductance element and said capacitance element of the first closed circuit in interconnected relation, the second closed circuit being coupled with said first closed circuit by said capacitance element; said first inductance element and capacitance element having values putting the first closed circuit in oscillating condition; said circuit device being in the form of a pulse generator circuit and said elements having values to satisfy the following conditions:

(1) fzf f where L inductance value of the first inductance element L inductance value of the second inductance element C:capacitance value of the capacitance element R resistance value of the first closed circuit R resistance value of the second closed circuit 4. A circuit device as claimed in claim 3, wherein the second inductance element of the second closed circuit includes a core of square-loop hysteresis magnetic material.

5. A nonlinear circuit device consisting of a first closed circuit which comprises a power source, a capacitance element and a first inductance element in interconnected relation; and a second closed circuit which comprises a voltage responsive switching element, a second inductance element and said capacitance element of the first closed circuit in interconnected relation, the second closed circuit being coupled with said first closed circuit by said capacitance element; said first inductance element and capacitance element having values putting the first closed circuit in oscillating condition; the switching element being a thyristor.

6. A device as claimed in claim 1 wherein 7 A circuit device as claimed in claim 1 wherein the first and second inductance elements are connected in series with the capacitance element connected to the inductance elements in Trelationship therewith.

8. A circuit device as claimed in claim 7 comprising resistances in series with each of said inductance elements.

9. A circuit device as claimed in claim 7 comprising a further inductance element in series with said capacitance element and coupled inductively with said second inductance element.

10. A circuit device as claimed in claim 7 comprising a further inductance element in series with said capacitance element.

11. A circuit device as claimed in claim 7 comprising a transformer between said first and second inductance elementsand including serially connected coils and a further capacitance element and switching element connected in 1r relationship with one of said coils.

12. A circuit device as claimed in claim 7 comprising a coil between said inductance elements and constituting with the second inductance element a transformer.

13. A circuit device as claimed in claim 3 wherein the first and second inductance elements are connected in series with the capacitance element connected to the inductance elements in T relationship therewith.

14. A circuit device as claimed in claim 13 comprising resistances in series with each ofsaid inductance elements 15. A circuit device as claimed Ill claim 13 comprising a further inductance element in series with said capacitance element and coupled inductively with said second inductance element.

16. A circuit device as claimed in claim 13 comprising a further inductance element in series with said capacitance element.

17. A circuit device as claimed in claim 13 comprising a transformer between said first and second inductance elements and including serially connected coils and a further capacitance element and switching element connected in 1r relationship with one of said coils.

18. A circuit device as claimed in claim 13. comprising a coil between said inductance elements and constituting with the second inductance element a transformer. I

19. A method for controlling a nonlinear circuit wherein first and second inductance elements connected in series with a voltage responsive switching element are further connected in T relationship and in first and second closed loops with a capacitance element which is in parallel relationship with said switching element, said method comprising making the relationship equal to less than zero wherein R, resistance in the first loop L inductance of the first inductance element. 

1. A nonlinear circuit device consisting of a first closed circuit which comprises a power source, a capacitance element and a first inductance element in interconnected relation; and a second closed circuit which comprises a voltage responsive switching element, a second inductance element and said capacitance element of the first closed circuit in interconnected relation, the second closed circuit being coupled with said first closed circuit by said capacitance element; said first inductance element and capacitance element having values putting the first closed circuit in oscillating condition; said circuit device being in the form of an oscillator circuit and said elements having values to satisfy the following conditions:
 2. A nonlinear circuit device as claimed in claim 1, wherein the second inductance element includes a core of ferrite magnetic material.
 3. A nonlinear circuit device consisting of a first closed circuit which comprises a power source, a capacitance element and a first inductance element in interconnected relation; and a second closed circuit which comprises a voltage responsive switching element, a second inductance element and said capacitance element of the first closed circuit in interconnected relation, the second closed circuit being coupled with said fiRst closed circuit by said capacitance element; said first inductance element and capacitance element having values putting the first closed circuit in oscillating condition; said circuit device being in the form of a pulse generator circuit and said elements having values to satisfy the following conditions:
 4. A circuit device as claimed in claim 3, wherein the second inductance element of the second closed circuit includes a core of square-loop hysteresis magnetic material.
 5. A nonlinear circuit device consisting of a first closed circuit which comprises a power source, a capacitance element and a first inductance element in interconnected relation; and a second closed circuit which comprises a voltage responsive switching element, a second inductance element and said capacitance element of the first closed circuit in interconnected relation, the second closed circuit being coupled with said first closed circuit by said capacitance element; said first inductance element and capacitance element having values putting the first closed circuit in oscillating condition; the switching element being a thyristor.
 6. A device as claimed in claim 1 wherein omega L2 1/ omega C . 7 A circuit device as claimed in claim 1 wherein the first and second inductance elements are connected in series with the capacitance element connected to the inductance elements in T relationship therewith.
 8. A circuit device as claimed in claim 7 comprising resistances in series with each of said inductance elements.
 9. A circuit device as claimed in claim 7 comprising a further inductance element in series with said capacitance element and coupled inductively with said second inductance element.
 10. A circuit device as claimed in claim 7 comprising a further inductance element in series with said capacitance element.
 11. A circuit device as claimed in claim 7 comprising a transformer between said first and second inductance elements and including serially connected coils and a further capacitance element and switching element connected in pi relationship with one of said coils.
 12. A circuit device as claimed in claim 7 comprising a coil between said inductance elements and constituting with the second inductance element a transformer.
 13. A circuit device as claimed in claim 3 wherein the first and second inductance elements are connected in series with the capacitance element connected to the inductance elements in T relationship therewith.
 14. A circuit device as claimed in claim 13 comprising resistances in series with each of said inductance elements.
 15. A circuit device as claimed in claim 13 comprising a further inductance element in series with said capacitance element and coupled inductively with said second inductance element.
 16. A circuit device as claimed in claim 13 comprising a further inductance element in series with said capacitance element.
 17. A circuit device as claimed in claim 13 comprising a transformer between said first and second inductance elements and including serially connected coils and a further capacitance element and switching element connected in pi relationship with one of said coils.
 18. A circuit device as claimed in claim 13 comprising a coil between said inductance elements and constituting with the second inductance element a transformer.
 19. A method for controlling a nonlinear circuit wherein first and second inductance elements connected in series with a voltage responsive switching element are further connected in T relationship and in first and second closed loops with a capacitance element which is in parallel relationship with said switching element, said method comprising making the relationship greater or less than zero wherein R2 resistance in the second L2 inductance of the second inductance element C the capacitance of the capacitance element while keeping equal to less than zero wherein R1 resistance in the first loop L1 inductance of the first inductance element. 